TAKE CARE BRETHREN LEST THERE SHOULD BE IN ANY ONE OF YOU: Blepete (2PPAM) adelphoi mepote estai (3SFMI) en tini: (Hebrews 2:1-3; 12:15; Matthew 24:4; Mark 13:9,23,33; Luke 21:8; Romans 11:21; 1 Corinthians 10:12) (See Torrey's list of Scriptures that speak of the needfulness of heedfulness - Heedfulness. Suggestion - Download  InstaVerse and then you can easily go through Torrey's Scripture references in context. You could use this topic in a Sunday School class, walking your class through the passages and simply listing what the class observes about the necessity to stay on the alert spiritually.)

Keep a watchful eye ever upon

Be seeing to it constantly, keep a watchful eye ever open

Spurgeon writes that...

The text naturally divides itself into an exhortation: Take heed, brethren a warrants: “lest there be in any of you an evil heart of unbelief;” and a description of the danger which would follow from a neglect of this warning: “in departing from the living God.” Lay up those three things in your memory and heart, and may God cause them to work there for the effectual blessing of your spiritual life. (Take Heed, Brethren - Pdf)

Take care (991) (blepo) means perceive with your eyes. Have your eye on this truth so as to beware of. The idea is to be constantly observing with a view to avoiding or constantly looking at in the sense of continuing to be wary.

As Spurgeon says...

No good ever comes of carelessness. He who never examines himself is sure to be self-deceived

Blepo is in the present tense (continual action called for = make this the habit of your life) active voice (choice of your will = the writer cannot force or coerce them) and imperative mood (command not a suggestion).

Be continually on your guard against enemies both within and without. The ruin of others should be a warning to us to take heed. Israel's fall in the Old Testament should sound a continual warning to all who might be tempted to walk the same crooked path. As Paul wrote...

Now these things happened as examples for us, that we should not crave evil things, as they also craved...Now these things happened to them as an example, and they were written for our instruction, upon whom the ends of the ages have come.  (1 Cor 10:6, 11)

Blepo is clearly a key word in the epistle to the Hebrews occurring 8 times in 13 chapters...

Hebrews 2:9 (note) But we do see Him who was made for a little while lower than the angels, namely, Jesus, because of the suffering of death crowned with glory and honor, so that by the grace of God He might taste death for everyone.

Hebrews 3:12 (note) Take care (present imperative), brethren, that there not be in any one of you an evil, unbelieving heart that falls away from the living God.

Hebrews 3:19 (note) So we see that they were not able to enter because of unbelief.

Hebrews 10:25 (note) not forsaking our own assembling together, as is the habit of some, but encouraging one another; and all the more as you see the day drawing near.

Hebrews 11:1 (note) Now faith is the assurance of things hoped for, the conviction of things not seen.

Hebrews 11:3 (note) By faith we understand that the worlds were prepared by the word of God, so that what is seen was not made out of things which are visible.

Hebrews 11:7 (note) By faith Noah, being warned by God about things not yet seen, in reverence prepared an ark for the salvation of his household, by which he condemned the world, and became an heir of the righteousness which is according to faith.

Hebrews 12:25 (note) See to it (present imperative) that you do not refuse Him who is speaking. For if those did not escape when they refused him who warned them on earth, much less will we escape who turn away from Him who warns from heaven.

Spurgeon comments on the command to take heed writing...

that we are all of us called upon to take heed. The word means that we are to be careful, to be watchful. True religion is not a thing that can be acquired by carelessness or neglect; we must take heed, or we shall never be found in the narrow way (see note Matthew 7:14).

You may go to hell heedlessly,
but you cannot so go to heaven.

Many stumble into the bottomless pit with their eyes shut, but no man ever yet entered into heaven by a leap in the dark.

Take heed, brethren. If ever there was a matter that needed all your thought, all your prudence, and all your care, it is the matter of your soul’s salvation. If you do trifle with anything, let it be with your wealth, or with your health, but certainly not with your eternal interests. I recommend all men to take heed to everything that has to do with this life, as well as with that which is to come, for in the little the great may be concealed, and the neglect of our estate may end in mischief to our immortal spirit. Certainly, the neglect of the body might lead to great injury to the soul; but if ever neglect deserves condemnation, it is when it concerns our higher nature; if we do not carefully see to it, that which is our greatest glory may become our most tremendous curse.

Brethren, the watchword for every one of us is, Take heed. You are an old Christian, but take heed. You are a minister of the gospel, and there are many who look up to you with veneration; but take heed. You have learned the doctrines of grace, and you know them well; there is little that any human being can teach you, for you have been well instructed in the things of the kingdom; but, still, take heed. Ay, and if you were so near to Heavengate that you could hear the song within, I would still whisper in your ear, Take heed.

Horses fall oftenest at the bottom of the hill when we, think that we need not hold them up any longer, and there is no condition in life which is more dangerous than that feeling of perfect security which precludes watchfulness and care.

He who is quite sure of his strength to resist temptation may be also equally certain of his weakness in the hour of trial.

God grant us grace, whatever sort of “brethren” we may be, to listen to the admonition of the apostle, “Take heed.”

(The writer) means, not only take heed for yourself, — though that is the first duty of each one of us, for every man must bear his own burden, and it becomes every prudent man to look well to the matter of his own salvation; — but the (writer) says, “Take heed, brethren, lest there be in any of you an evil heart of unbelief.”

You are to watch over your brethren, to exhort one another daily, especially you who are officers of the church, or who are elderly and experienced.

Be upon the watch lest any of your brethren in the church should gradually backslide, or lest any in the congregation should harden into a condition of settled unbelief, and perish in their sin.

He who bids you take heed to yourself, would not have you settle down into a selfish care for yourself alone, lest you should become like Cain, who even dared to say to the Lord himself, “Am I my brother’s keeper?” Nothing can be more horrible than the state of mind of a man whose talk is like to that of Cain, who slew his brother. “Take heed,” therefore, ye who are in the Church of God, not only to yourselves, but to those who are round about you, especially to such as are of your own family. (Take Heed, Brethren - Pdf)

That there not be - When blepo is followed as it is in this passage by a negative particle (mepote) and the indicative mood, it expresses a warning and fear regarding a present inevitable reality and indicates the warning should be taken very seriously. Having reminded his readers of the defection of the wilderness generation, the writer proceeds to warn them against committing a similar sin. So it could read "that there not be certain ones who I cannot name who actually apostatize from the living God".

Regarding the command to take care, J C Ryle writes

Believe me, this world is not a world in which we can do well without thinking, and least of all do well in the matter of our souls.

Consider your ways says God to Israel through the prophet Haggai (Hag 1:5,7) says the Word of God--stop and think--consider and be wise.

We do well to remember the Spanish proverb that says...

Hurry comes from the devil.

Young men run into sin, and then say, "I did not think about it--it did not look like sin." Not look like sin! Would we expect sin to come to us saying, "I am sin". How much easier to avoid if it were so obvious.  One problem is that sin usually seems "good, and pleasant, and desirable" when it is being committed. But as the wisest man of the Old Testament warned...

Watch the path of your feet, and all your ways will be established. (Pr 4:26)

But truth is not productive if we don't act upon it, which is what even the writer Solomon failed to do as shown in the tale of his tragic downfall in first Kings...

Now King Solomon loved many foreign women along with the daughter of Pharaoh: Moabite, Ammonite, Edomite, Sidonian, and Hittite women, 2 from the nations concerning which the LORD had said to the sons of Israel, "You shall not associate with them, neither shall they associate with you, for they will surely turn your heart away after their gods." Solomon held fast to these in love. 3 And he had seven hundred wives, princesses, and three hundred concubines, and his wives turned his heart away.4 For it came about when Solomon was old, his wives turned his heart away after other gods; and his heart was not wholly devoted to the LORD his God, as the heart of David his father had been. 5 For Solomon went after Ashtoreth the goddess of the Sidonians and after Milcom the detestable idol of the Ammonites. 6 And Solomon did what was evil in the sight of the LORD, and did not follow the LORD fully, as David his father had done). (1Kings 11 )

Brethren (80) (adelphos from collative a = denoting unity + delphús = womb) is literally one born from same womb and so a male having the same father and mother as reference person. Figuratively adelphos in this verse refers to a close associate of a group of persons having well-defined membership. The author addresses his readers in terms of their confession of faith (v1) as “brethren,” yet also recognizes that some within the Christian fellowship may have an “evil heart of unbelief” (Heb 12:15-17). Christ saves completely those who come to God through Him (Heb 7:25), but Christians must guard their own and each other’s endurance by encouraging one another (Heb 10:24, 25), as the author does throughout this letter (Heb 13:22).

Spurgeon writes that...

THIS message is not addressed to strangers far away, but to brethren. Paul (Ed note: CHS feels Paul wrote Hebrews but most modern scholars doubt Paul is the author) wrote it to the Hebrews, who were his brethren according to the flesh; it was kind of him to call them by that name.

He also, writes it to all of us who are believers in Christ, and we ought to receive his word with all the greater intensity of attention because he writes to us as his brethren. The term applies to all who are brethren in Christ, — really so, — those who are quickened by the one Spirit, made children of the one Father, and going to the one heavenly home. The apostle would not have us begrudge this title to any genuine member of our Lord Jesus Christ’s true Church. It is not for us to read men’s hearts; we have not the Lamb’s Book of Life in our possession, so we cannot discover whether such-and-such a man’s name is really written in it, or not; but, in the judgment of Christian charity, all those who have joined themselves to Christ’s Church are our brethren, and the more we recognize that relationship, the better. To all of you, therefore, who bear the Christian name, this message comes with power, “Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.”

There are other persons, who are associated with us in our congregations, who do not profess as yet to have passed from death unto life, although they come up with us to the house of the Lord. They swell the chorus of our praise, they bow their heads with us in prayer, they are in many respects our fellow-worshippers, and they have, apparently, a warm heart towards good things, though not yet fully one with us in the highest spiritual sense. We will not exclude them from this message, for they are our brethren as men, even if they are not our brethren as Christians, and the word comes to them as well as to us who are avowedly on the Lord’s side, “Take heed, brethren, lest there be in any of you an evil heart of unbelief.” (Take Heed, Brethren - Pdf)

Lest there should be - These words are in a Greek construction which indicates that there is a fear that the thing spoken of might occur or that there is a suspicion that it might occur.

Any one - This  means someone, a certain one. Particularly and generally of some person or thing whom the writer cannot or does not wish to name or specify particularly.

Any one of you - This could be rendered “in any certain individual of your number” which indicates that the writer is appealing to each one individually.

The UBS Handbook explains that...

No one among you makes it clear that at this point the writer is not afraid that the whole community to which he is writing will lose its faith, but that some individuals within it may do so. (Ellingworth, P., & Nida, E. A. A Handbook on the Letter to the Hebrews. UBS Handbook Series. New York: United Bible Societies or Logos)

AN EVIL AND UNBELIEVING HEART: kardia ponera kardia ponera apistias: (10; Genesis 8:21; Jeremiah 2:13; 3:17; 7:24; 11:8; 16:12; 17:9; 18:12; Mark 7:21-23)  (See these topical studies - Heart, Character of the Unrenewed) (Heedfulness; Rebellion Against God; Self-will and Stubbornness; Unbelief)

Evil (4190) (poneros from pónos = labor, sorrow, pain) (see related word poneria) refers to evil and means active evil in opposition to good. When Satan is referred to as the "Evil One", the NT writers chose poneros rather than kakos, this latter word basically denoting a lack of something (it is not as it ought to be and thus is bad) but also used to refer evil in a moral sense.

Evil in the abstract is kakos, but poneros is used in this passage to indicate an evil which actively harmful and hurtful and actively opposed to good.

Hiebert adds that poneros...

State another way the kakos man may be content to perish in his own corruption, but the poneros man is not content unless he is corrupting others as well, and dragging them down into the same destruction with himself. The English word which best translates this Greek word is “pernicious.”

Paul uses poneros in Galatians writing of the Lord Jesus Christ...

Who gave Himself for (~ His substitutionary atonement) our sins, that He might deliver (rescue out of) us out of this present evil (poneros) age ("world order"), according to the will of our God and Father (Galatians 1:4)

Unbelieving (570)(apistia from a = without + pistos = believing, faithful) is literally "not believing" and thus describes a lack of faith (unfaithfulness). It describes an unwillingness to commit oneself to another or respond positively to the other’s words or actions.

The idea in context is not simply the danger of disbelief, but of a refusal to believe. The genitive case describes the evil...heart as marked by unbelief. Stated another way, the Greek grammar indicates the content of an evil heart. This evil heart of unbelief which the writer suspects may be the condition of some of his readers, is a heart in which the evil of unbelief is present in an active, pernicious condition which manifests itself in active opposition. The great fear of the writer is that this pernicious attitude would result in a deliberate and final rejection of the good news of salvation in Christ.

To reiterate, there is a difference between a heart in which unbelief is present, and an unbelieving heart. True believers can have elements of unbelief in their heart but do not have an unbelieving heart which describes a person who is not born again. The person who has an unbelieving heart is solely and entirely controlled by unbelief and there is no faith whatever. If some of the Hebrews had this kind of heart they were not saved. They may have given intellectual assent acknowledging that Jesus was the Messiah but they had not without submitted to and fully trusted in that liberating truth.

Spurgeon addresses genuine believers (dearly beloved, this note is long but is worth reading) who can experience varying degrees of unbelief writing ...

dear friend, even you may fall into unbelief. Are you not aware of that fact? Have you not been already tormented with it? I daresay, like myself, you did at one time indulge the idea that old Incredulity would soon die. You took him by the heels, and you put him in the stocks, and you said to yourself,

“He will never trouble me again; I shall never doubt the promise of God any more as long as I live. I have had such a wonderful experience of God’s faithfulness, he has been so exceedingly gracious to me, that I cannot doubt him any more.”

You remember how Mr. Bunyan says, in Holy War, that, after the enemies of King Shaddai had been sentenced to death,

“One of the prisoners, Incredulity by name, in the interim betwixt the sentence and time of execution, brake prison, and made his escape, and gets him away quite out of the town of Mansoul, and lay lurking in such places and holds as he might, until he should again have opportunity to do the town of Mansoul a mischief for their thus handling of him as they did.”

Incredulity will work his wicked will upon you if he can, and you must ever remember that it is possible even for you to fall into unbelief, — you who are rejoicing, you who have hung out all your flags, and are keeping high festival, — oh, tell it not in Gath! — even you may yet be found doubting your God. May the Lord grant that you may be delivered from this evil! But it is only almighty grace which can keep you with faith pure and simple, and free from any tincture of doubt and unbelief.

Pressure of circumstances may drive you into an unbelieving state of mind. Depression of soul, due to physical causes, may do it; the spirit often truly is willing and believing, but the flesh is weak, and it may pull you down. Association with doubters may have a similar effect. Conflict for the truth may make you familiar with the poisoned arrows of skeptics, and in attempting to do them good you may imbibe mischief from them.

The Lord will preserve you from the positive, stark, black Egyptian darkness of unbelief; but there are other grades and degrees of it which you may have to endure. It is bad for a Christian to have any admixture of darkness with his light, and to have any measure of doubt mingled with his faith; yet it may be so, and therefore the Spirit of God says to the people of God, “Take heed, lest there be in any of you an evil heart of unbelief, in departing from the living God.”

Note, next, that in proportion as unbelief does get into your heart, you will be in to depart from the living God. I am not speaking now of open glaring sin; you have not fallen into that, and I pray God that you never may. But, beloved, we may have all the decencies of morality, and all the proprieties of Christian conduct, and yet we may be all the while “departing from the living God.” The moment we begin to trust in man, and to make flesh our arm, we have to that extent forgotten Jehovah, and departed from the living God. The moment our heart’s deepest affections twine about the dearest creature, — be it husband, or wife, or child, — we are to that degree “departing from the living God.” To the true believer, in his best estate, the sweetest line that he can ever sing, is that which we sang just now, —

“Yea, mine own God is He.”

That is the circle which surrounds all his joy; it is the center of his soul’s highest delight. He has God for his very own. On his God he relies, and towards him he sends out the full streams of his earnest affection.

Remember what the Lord wrote by the pen of the prophet Jeremiah:

“Cursed be the man that trusteth in man: and maketh flesh his arm, and whose heart departeth from the Lord. For he shall be like the heath in the desert, and shall not see when good cometh; but shall inhabit the parched places in the wilderness, in a salt land and not inhabited. Blessed is the man that trusteth in the Lord, and whose hope the Lord is. For he shall be as a tree planted by the waters, and that spreadeth out her roots by the river, and shall not see when heat cometh, but her leaf shall be green; and shall not be careful in the year of drought, neither shall cease from yielding fruit:”

Brothers, it is easy to depart from the living God spiritually, — gradually to lose that serene and heavenly frame which is our highest privilege, to forget Him Who ought ever to be before our eyes as the chief factor in our entire life, the great All-in-all, compared with Whom everything else is but as a dream, a fleeting shadow.

I bear my witness that, to walk with the living God, is life; but to get away from Him, is death; and that, in proportion as we begin to depart and put a distance between ourselves and the great Invisible, in that proportion our life ebbs away, and we get to be sickly, and scarcely alive. Then doubts arise as to whether we are the people of God at all; and it is sad that such a question as that should ever be possible.

We ought to live like the angel whom Milton pictures as living in the sun, — in the very center of the orb of light, — so near to God that we do not merely sometimes enjoy His presence, but that in Him we live altogether, and never depart from Him. I remember a minister calling upon a poor old saint, and before coming away he said he hoped that the Divine Father would constantly visit the sick man; but he replied,

“O sir, I do not want you to ask that the Father should merely visit me, for by these many months together He has been abiding with me, and I have been abiding in Him.”

 So may it be with each one of you, my brethren; and that it may be so, give attention to the message of the text: “Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing “ — in any measure or degree — “from the living God.”

“But,” say you, “wherefore should we take such heed about that matter? We are believers, and, therefore, we are saved.” Are you believers? They who can trifle with heavenly things are not true believers in the Lord Jesus Christ; and if ever it becomes a thing of small importance to you whether you dwell with the living God, or not, the question may well arise in your heart,

“Am I truly a believer in Jesus Christ with the faith of God’s elect, — the faith that really saves the soul?”

But, my brethren, if you do not continue steadfast and firm in your faith in its simplicity, if your evil heart of unbelief begins to prevail, and you are turned aside from your confidence in Christ, and so begin to get away from God, you will be great losers thereby even if you do manage to get to heaven, “saved, yet so as by fire.”

YOU WILL LOSE YOUR JOY

For, first, you will lose your joy. That is no small thing. “The joy of the Lord is your strength.” The joy of the Lord is one of the means by which you are to be made useful. The joy of the Lord sweetens trial, lightens care, and turns service into delight but if you lose that joy, you are as one who travels alone in the dark, and who stumbles and falls. I pray you, do not depart from the living God in any degree, for if you do so, your joy will begin to get clouded, the brightness and the warmth of it will be taken from you, and you will become faint-hearted, trembling, timorous, and sad. If the evil heart of unbelief shall prevail against you, depend upon it you will lose your joy.

YOU WILL LOSE YOUR ASSURANCE

Then you may be certain, also, that you will lose your assurance. Full assurance cannot exist with unholiness. One has well said,

“If thine assurance doth not make thee leave off sinning, thy sinning will make thee leave off enjoying assurance;”

and I am sure that it is so. If we begin to look to second causes, and do not trust in God, we shall then put forth our hand to some one sin or another; and when we do that, we cannot be certain that we are children of God at all.

That man who feels sure of his safety, and yet can play with sin, and find pleasure in it, may be assured of his own damnation.

I remember, in my boyhood, one, who never talked so religiously as when he was the worse for drink; and in public, before ungodly men, he used to boast of his full assurance of salvation, when he was much too far gone to be assured that he would get home in safety that night. That kind of conduct is atrocious, and no one would excuse it for a moment; we know that men who talk so only proclaim their own shame to their own eternal disgrace. But do not let any of us indulge even in a measure of that kind of sin. That, evil heart of unbelief will not only lead us away from a holy walk with God, but it will also take from us our assurance if it is an assurance that is worth, the having.

YOU WILL LOSE YOUR FRUITFULNESS

Then, next, it will take from us our fruitfulness. Dear child of God, I am sure that you do not wish to live here without doing good to others; but how can you do good if you are not yourself good?

You cannot bring forth fruit unto holiness unless you are watered with the dew of heaven, and the sunlight of God shines upon you; and you will not have either of those blessings if you live carelessy, and if you fall into an unbelieving state of mind, and get away from contact with the everliving God.

If any of you have tried this kind of life, you must have become painfully aware what it is to have all the sap and. juice, out of which the clusters ought to come, dried up within the tree, and everything turned to barrenness because you have yourself departed from God.

YOU WILL LOSE PURITY

These are all serious losses to a child of God; it is no light matter for you to lose joy, and assurance, and fruitfulness; but the evil heart of unbelief will cause you also to lose purity. There is a delicate bloom upon the fruit that grows in Christ’s garden, where He, as the Gardener, cultivates it with tender care; but sin comes, and rubs away that bloom, and spoils the fruit. If you and I fall into sin, we shall have to weep bitterly over it; we shall not be able to enjoy the high privilege which belongs to those who keep their garments unspotted from the world. Of these the Savior says, “They shall walk with me in white: for they are worthy.”

I believe that, of all fortes of spiritual loss, one of the worst is to lose tenderness of conscience, quickness of apprehension when sin is near, — to lose a sense of cleanness of heard.; and of sanctification by the Spirit of God.

When those are gone, we are something like Adam when he lost Paradise, and we turn our faces back again toward that purity, and cry to the Lord to restore it, as we moan rather than sing, —

“Where is the blessedness I knew
When first I saw the Lord?”

Take care that you do not lose it, for it will hardly be likely to be restored to you in the same degree as you had it at the first.

The child of God who wanders away also loses peace, and many other attainments of the spiritual life. He is like a boy who is sent down from the top of the class; it may take him a long time to get up again. Or he is like the man who has risen from the ranks, but who has misbehaved himself, and is therefore made a private again. He who once could lead the people of God has to be very thankful that he is permitted to go into the rear rank, and to follow where others lead, he who could talk for God boldly now has to sing very small, and let others speak. He who used to encourage others now needs to be encouraged himself. He was once strong in faith, and a mighty man of valor, but now he has to use Mr. Ready-to-halt’s crutches, and to go along with the feeble ones among the pilgrims, because an evil heart of unbelief has made him depart from the living God.

YOU WILL LOSE INFLUENCE

This brings, of course, a loss of influence with the people of God, and with worldlings, too; for when a man has injured his reputation, it is not soon repaired again. If he has slipped and fallen, brethren weep over him, and love him, and seek to restore him, but they do not trust him as they used to do. They are some little while before they dare to follow where he leads the way. I have seen a man, whose judgment was like that of Solomon, whose position in the midst of his brethren was that of a hero inciting them to daring deeds; but he has fallen, and all Israel has wept over him. Perhaps there has been no shameful sin, but yet there has been an evident decline in spirituality, and in force and power. The Lord has left him, and great Samson, though he shakes himself as aforetime, is fast bound in chains, and his eyes have been put out. Happy will he be if, at; some future day, when the locks of his hair have grown again, he shall be able, to pull down the temple of the Philistine lords upon them; but so far as his brethren are concerned, he will have to be the object of loving pity rather than of joyful confidence.

YOU WILL LOSE POWER IN PRAYER

Do not tell me, then, that you do not lose anything by getting into a state of unbelief, and departing from God, for, in addition to all this, such a child of God loses power in prayer. It is

“the effectual fervent prayer of a righteous man” that “availeth much.”

Our Lord Jesus told his disciples,

“If ye abide in me, and my words abide in you, ye shall ask what ye will, and it shall be done unto you.”

But disobedient children will find that the Father will turn a deaf ear to their supplication. “No,” he will say, “you would not hearken to me, neither will I hearken to you,” for God has a way of walking contrary to them that walk contrary to Him. Then there very often follow, at the back of that, chastisements heavy and multiplied.

Take heed, my brethren, as ye remember the history of David. What a blessed life, what a glorious life, is that of David until the unhappy day when kings went forth to battle, but the king of Israel went not! He tarried in inglorious ease at home, and as he walked upon the top of his palace, he saw that which tempted him to ill desire, to that ill desire he fell a prey, and the man after God’s own heart became an adulterer and a murderer. Alas! alas! All the rest of his life he travels on toward heaven with broken bones and sorrowful spirit. At every step, he limps; his prayers are sighs; his psalms lack the jubilant notes that once made them ascend joyously unto the Lord. He is a true man of God still, and in his deep repentance he becomes a pattern to us all in repenting of sin; but the brave joyous David is not there, and at the last, though he pleads the covenant, he has to say,

“Although my house be not so with God.”

There was a great mass of heart-break packed away in those few words, more than we need to explain just now. What a dreadful family David had! None of us have had a family like his; that was his chastisement in his own children. What a mercy it was for him that sovereign grace did not cast him away after he had uttered that deep bass note,

“Although my house be not so with God,”

then came the sweet assurance of faith, “Yet He hath made with me an everlasting covenant, ordered in all things, and sure, although He make it not to grow.” There came in again the note of deep sorrow mingled with his holy faith in God. O brothers, I have heard men say that a broken leg, when it is mended, is sometimes stronger than it was before. It may be so; but I am not going to break my leg to try the experiment. I know one who says that his arm was broken when he was a boy, and that he believes it is stronger than the other one. So it may be; but I will not break my arm if I can help it. May the Lord rather keep me in His hands lest I dash my foot against a stone There is a great deal of experience which I hope you will never have, and that is the kind of experience which comes of an evil heart of unbelief, in departing from the living God. Take heed that you never come to know that sorrow. (Take Heed, Brethren - Pdf)

PROFESSING
CHRISTIANS

Spurgeon goes on to describe those had full blown unbelieving hearts and were thus professors but not possessors of the new life in Christ...

Now, in the second place, and very briefly, I want to apply my text to All In The Visible Church, whether they are indeed God’s people or not. If you profess to belong to Christ, it is enough for my present purpose. “Take heed,” I pray you, professing Christians, “lest there be in any of you an evil heart of unbelief, in departing from the living God.”

For, first, many professors have had an evil heart. It is not every church-member who has a new heart and a right spirit. Judas was in the church, but he had an evil heart, and was a devil. It may be so with me, my brother, or with you. There are some in the church who have no real faith in Christ. Their very heart is crammed full of unbelief, though they pretend that they have believed in Christ. I know that it is so; we cannot help observing that there are unbelievers who bear the name of Christians.

Many of these have turned aside. To our sorrow, we have lived to see it in far too many cases; they were members of churches, but they grew weary of the good way. Nothing pleased them; the preacher who used to charm them has lost all his power over them. Prayer-meetings are dull, and they would rather not have anything at all to do with religion. We have known some go back to the world for no reason that they dared even to tell themselves; it was because of the fickleness of their unregenerate spirits.

We have seen this happen to others when they have been strongly tempted. Satan knew their particular weakness, and he assailed them there. How many professors have given way to strong drink! They would have a little, and who could condemn them? But when they began by taking a little, they soon took what was not little to others, and it turned out by-and-by not to be little to themselves; and he who should have been a pattern of self-denial to the people of God, has become a victim of intoxication.

Others have fallen through the lusts of the flesh, the lust of the eye, and the pride of life. A man has been tempted to get gain by dishonesty; at first, the bribe did not affect him; but it was doubled, or trebled, and then he fell.

Many more have we seen very gradually turning aside; it was almost impossible to tell exactly when they left the line of strict integrity; it was only by a heir’s breadth that they turned aside at first, but afterwards their apostasy was visible to all.

Some have been frost-bitten; they’ have grown lukewarm, and then at last icy cold, and we have lost them.

Some professors have been turned aside by pride. They were too rich to join with any but a “respectable” worldly church; or they were so learned — so conceited, is the right word — that the plain gospel was too inferior an article for their profound minds!

Some, alas! — and I fear, very many, — have turned aside through poverty. We meet with cases where the visitor in the lowest haunts of degradation says that he has come across a woman in the depths of penury, and with scarcely rags enough to cover her, yet she has produced a communion ticket, for in better days she was a member of the church, but she could not get clothes quite good enough, as she thought. She fancied that she would be looked down upon if she came when poor, and so she ceased to attend the means of grace, and by-and-by gave up everything like a profession of religion. Oh, if there are any members of the church of that sort here, I pray you, if you ever do become very poor, do not go away from us because of that; and if your clothes should be all rags, I am sure that none of us will despise you, or if there should be any who do so, I will bear the responsibility of despising them; but do not you ever stay away from the house of God, or the company of your Christian brethren and sisters, because of poverty. Why, it seems to me that, the less you have of earthly good things to comfort you, the more you want of divine treasure and the companionship of Christ; and you should rather seek the society of your friends in Christ than for a moment to shun it.

Yet it has been so, and therefore I put it to all here who profess to be followers of Christ: “Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.”

"CAMP
FOLLOWERS"

Now I have only a very few minutes left in which to apply my text To Those Who Are Simply In The Congregation.

There is a large number of you, who come to worship with us, who are only camp-followers. You are not in the regular regiments of the Lord’s army, yet you cling to us, and we cannot help regarding you with much affection as “brethren” so far as you allow that brotherhood to be true. We wish that you would make it truer still, but we do not want any of you to perish because of your unbelief.

Remember, dear friends, that your unbelief is an affair of your heart. It is not an evil head of unbelief, but “an evil heart of unbelief” of which the apostle speaks; and that is what is wrong with you.

You know that you believe everything that is in the Bible; you look with horror upon any heretical doctrine; you love to hear the gospel, and yet you have not received it for yourselves. I want you to do my Lord the credit to think Him no liar; but a true Savior; and if He be such, then come and trust Him. You are fit to come to Him, for your fitness lies in your need of Him, and I am sure you need Him. Come and do Him this act of justice, — trust Him. He is so strong, so true, so tender, that if you will but commit your staff to Him, He will take care of it. If you will bring your sins to Him, he will wash them away. If you will bring your weakness to Him, He will strengthen you. If you will really come to Him, He will take you as you are at this moment, for He never did cast out one who came to Him; it is not like Him, He could not do it. It is no more possible for Christ to reject a sinner who trusts him than it is for God to lie. It is contrary to the nature of God, and he cannot do what is contrary to himself. Come, then, and do not depart from the living God by an evil heart of unbelief. Nothing will bring you near to God but believing; and nothing can shut you out from God, and from the life and light and liberty that there is in God in Christ Jesus, but your unbelief. Only trust him; that is the whole of the mariner. I pray God, of his infinite mercy, to make you “take heed, lest there be in any of you an evil heart of unbelief,” which shall get such mastery over you, that you shall depart, not only from the living God, but even from the ways of morality, till God shall say to you, at the last, “Depart, ye cursed. You always were departing, keep on departing.” And this shall be the punishment of your sin; you shall reap it fully developed, for hell is sin full-grown. God save us from the babe, which is sin, that we may not know the man, which is hell; — save us from the seed, which is sin, that we may not know the harvest, which is hell; — save us from the spark, which is sin, that we may not know the conflagration, which is eternal damnation! God save and bless you, dear friends, for Jesus Christ’s sake! Amen. (Take Heed, Brethren - Pdf)

Heart  (2588)(kardia) in the NT does not refer to the physical organ that pumps blood but always refers (figuratively) to the seat and center of human life. The heart is the center of one's personality, and as such it controls one's intellect, emotions, and will.  If one has a believing heart, such a heart is the wellspring of this person's spiritual life. You do what you do because you believe what you believe in your heart. As Jesus taught "the mouth speaks out of that which fills the heart" (Mt 12:34). What fills your heart as you read these notes? You can know by what has come out of your mouth over the past few days. Remember that "the good man out of the good treasure of his heart brings forth what is good (agathos)" (Luke 6:45).

IN FALLING AWAY FROM THE LIVING GOD: en to apostenai (AAN) apo theou zontos (PAPMSG): (Hebrews 10:38; 12:25; Job 21:14; 22:17; Psalms 18:21; Proverbs 1:32; Isaiah 59:13; Jeremiah 17:5; Hosea 1:2)

Falling away from (868) (aphistemi from apo = separation of one thing from another + histemi = stand) literally means to stand off from (English = apostasy), to withdraw, forsake, depart from or remove oneself from.

It is important to emphasize that this verse does not justify the false teaching that one can lose one's salvation. Examine the context, noting that the evil and unbelieving heart is the reason they fall away. They are not genuine believers.

Vincent explains that departure from the living God is...

The characteristic of unbelief. Faith is personal union with God. Unbelief separates from God.

Matthew Henry writes...

An evil heart of unbelief is at the bottom of all our sinful departures from God; it is a leading step to apostasy; if once we allow ourselves to distrust God, we may soon desert him.

Aphistemi does not mean that at one time they belonged to God and now they no longer belong to Him, but rather that they stood away from God, never having belonged to Him. The same is true with first Timothy where we read...

But the Spirit explicitly says that in later times some will fall away (aphistemi) from the faith, paying attention to deceitful spirits and doctrines of demons, (1 Timothy 4:1)

Aphistemi is also used by Luke in connection with the Jesus' explanation of the seed that falls on stony ground...

And those on the rocky soil are those who, when they hear, receive the word with joy; and these have no firm root; they believe for a while, and in time of temptation fall away (aphistemi). (Luke 8:13)

Jesus says they fall away because the seed of the Word of God failed to take root. Aphistemi does not indicate uprooting because there never was a root and thus there this person was not a believer.

Kenneth Wuest comments on “stand off from”...